PCR primers for cDNA amplification were designed using the Primer3 server. Each gene was divided into five fragments, covering the whole coding region of the gene. The forward (F) and reverse (R) primers and size of the each PCR product are listed below
| Gene/fragment | Primer sequence (5′→3′) | Product size (bp) |
| SMAD2 | F: ATGTCGTCCATCTTGCCATT | |
| Fragment 1 | R: CCTTTTCGATGGGATACCTG | 365 |
| SMAD2 | F: CCAGGTCTCTTGATGGTCGT | |
| Fragment 2 | R: TATATCCAGGAGGTGGCGTT | 354 |
| SMAD2 | F: TATTCCAGAAACGCCACCTC | |
| Fragment 3 | R: GCACTCAGCAAAAACTTCCC | 400 |
| SMAD2 | F: TGCCACGGTAGAAATGACAA | |
| Fragment 4 | R: AAGGGGATCCCATCTGAGTT | 413 |
| SMAD2 | F: AATGTGCACCATAAGAATGAGTT | |
| Fragment 5 | R: TTCCATGGGACTTGATTGGT | 202 |
| SMAD3 | F: CCAGCCATGTCGTCCATC | |
| Fragment 1 | R: AAGGCGAACTCACACAGCTC | 344 |
| SMAD3 | F: ATGTCATCTACTGCCGCCTG | |
| Fragment 2 | R: ATTCGGGGATAGGTTTGGAG | 377 |
| SMAD3 | F: TGGCTACCTGAGTGAAGATGG | |
| Fragment 3 | R: CCTCCGATGTAGTAGAGCCG | 357 |
| SMAD3 | F: TAGGGCTGCTCTCCAATGTC | |
| Fragment 4 | R: TGTCTCCTGTACTCCGCTCC | 349 |
| SMAD3 | F: GGCTTTGAGGCTGTCTACCA | |
| Fragment 5 | R: AACATCCACCTCTGGGTTTG | 382 |
| SMAD4 | F: TTTCCAAAGGATCAAAATTGC | |
| Fragment 1 | R: TTGTGAAGATCAGGCCACCT | 385 |
| SMAD4 | F: GATCTATGCCCGTCTCTGGA | |
| Fragment 2 | R: GTGGAAGCCACAGGAATGTT | 387 |
| SMAD4 | F: CTGCCAACTTTCCCAACATT | |
| Fragment 3 | R: GGGTCCACGTATCCATCAAC | 436 |
| SMAD4 | F: CCATTTCCAATCATCCTGCT | |
| Fragment 4 | R: CGATGACACTGACGCAAATC | 480 |
| SMAD4 | F: GATTTGCGTCAGTGTCATCG | |
| Fragment 5 | R: TGATAAGGTTAAGGGCCCCA | 378 |